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    <title>Document</title>
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    <div id="coco" getTime="getTime123" data-index="data-index" data-list-name="data-list-name"></div>
    <script>
        var div = document.querySelector('div');
        console.log(div.getAttribute('getTime'));
        /* 
        1. 约定大于规范，规范大于编码。自定义属性都已data- 开头
        2. 返回值是一个对象。属性是data- 作为前缀
        3. 属性名 data- 默认省略 小驼峰
        */
        console.log(div.dataset);

        console.log(div.dataset.index);
        console.log(div.dataset.listName);
    </script>
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